// Complexity depends on the type of operations that were performed
// since the last checkpoint; each Set* operation creates an undo
// pass which Undo has to revert with a worst-case complexity of O(n).
func (po *poset) Undo() {
	if len(po.undo) == 0 {
		panic("empty undo stack")
	}
	if debugPoset {
		defer po.CheckIntegrity()
	}

	for len(po.undo) > 0 {

	userArenaChunkPages = userArenaChunkBytes / pageSize

	// userArenaChunkMaxAllocBytes is the maximum size of an object that can
	// be allocated from an arena. This number is chosen to cap worst-case
	// fragmentation of user arenas to 25%. Larger allocations are redirected
	// to the heap.
	userArenaChunkMaxAllocBytes = userArenaChunkBytes / 4
)

func init() {

   * negation is cheaper to precompute than the matcher itself; it tries to build small hash tables
   * for matchers that only match a few characters, and so on. In the worst-case scenario, it
   * constructs an eight-kilobyte bit array and queries that. In many situations this produces a
   * matcher which is faster to query than the original.
   */
  @GwtIncompatible // SmallCharMatcher

	// for File Header, Auxiliary Header, and Section Headers.
	// May waste some.
	XCOFFHDRRESERVE = FILHSZ_64 + AOUTHSZ_EXEC64 + SCNHSZ_64*23

	// base on dump -o, then rounded from 32B to 64B to
	// match worst case elf text section alignment on ppc64.
	XCOFFSECTALIGN int64 = 64

	// XCOFF binaries should normally have all its sections position-independent.

		// to determine whether a given feature is supported,
		// we may receive a positive response even if the feature is not supported.
		//
		// In this very rare scenario, the worst case will be that this
		// request will wait for 3 seconds before it fails.
		if etcdfeature.DefaultFeatureSupportChecker.Supports(storage.RequestWatchProgress) && c.watchCache.notFresh(requestedWatchRV) {

	i scavengeIndex
}

func NewScavengeIndex(min, max ChunkIdx) *ScavengeIndex {
	s := new(ScavengeIndex)
	// This is a bit lazy but we easily guarantee we'll be able
	// to reference all the relevant chunks. The worst-case
	// memory usage here is 512 MiB, but tests generally use
	// small offsets from BaseChunkIdx, which results in ~100s
	// of KiB in memory use.
	//
	// This may still be worth making better, at least by sharing

		// We're assuming here that all the keys in the map literal are distinct.
		// If any are equal, this will be an overcount. Probably not worth accounting
		// for that, as equal keys in map literals are rare, and at worst we waste
		// a bit of space.
		n.Len += int64(len(dynamics))

		return m
	}

	// No return - type-assertions above. Each case must return for itself.
}

      }
    }
  }

  /**
   * Marks the given node as 'deleted' (null waiter) and then scans the list to unlink all deleted
   * nodes. This is an O(n) operation in the common case (and O(n^2) in the worst), but we are saved
   * by two things.
   *
   * <ul>
   *   <li>This is only called when a waiting thread times out or is interrupted. Both of which
   *       should be rare.

      }
    }
  }

  /**
   * Marks the given node as 'deleted' (null waiter) and then scans the list to unlink all deleted
   * nodes. This is an O(n) operation in the common case (and O(n^2) in the worst), but we are saved
   * by two things.
   *
   * <ul>
   *   <li>This is only called when a waiting thread times out or is interrupted. Both of which
   *       should be rare.

		// scavenging throughput.
		//
		// The current value is chosen assuming a cost of ~10µs/physical page
		// (this is somewhat pessimistic), which implies a worst-case latency of
		// about 160µs for 4 KiB physical pages. The current value is biased
		// toward latency over throughput.
		const scavengeQuantum = 64 << 10

		// Accumulate the amount of time spent scavenging.